Early attempts to construct a portable partition or screen are illustrated by U.S. Pat. No. 193,573 to Tripp, U.S. Pat. No. 376,436 to Harrison, U.S. Pat. No. 3,314,468 to Riedel, U.S. Pat. No. 4,124,196 to Hipskind, and U.S. Pat. No. 4,186,912 to Byrd, Jr. Each of these patents discloses a screen which can restrict the view and access to certain areas or scenes, such as an accident scene. Although portable, the bulkiness and cumbersome handling of these screens make them impractical for use as a crowd barrier system.
Both Williams, in U.S. Pat. No. 1,832,271, and Garrett and Shelton, in U.S. Pat. No. 3,408,771, disclose cords or cables which can extend across aisles or form railings These cords or cables, though, are of a fixed length and the barriers produced therewith are not adjustable without sagging or otherwise becoming aesthetically undesirable and less effective.
Similarly, in U.S. Pat. No. 2,392,755, Michaels discloses a flexible guard railing which can extend across an open space between two stanchions. Fink, in U.S. Pat. No. 3,917,231, discloses a flexible traffic barrier which comprises an elongated strip of flexible material positioned on a reel, carried on a vertical support, such that the flexible material can be unrolled and positioned across an area to provide a barricade. In U.S. Pat. No. 4,844,420, Oster discloses a retractable crowd control barrier which consists of a housing carried on a post or stanchion in which an elongated tape is stored on a spring actuated spool assembly. The tape can be extended from the housing and positioned to guide pedestrian traffic.
Crowd control barrier systems which utilize mechanized devices, such as the spools or reels of Fink and Oster, and which require either manual or other type of actuation, such as spring actuation, have several disadvantages. Most notable of these is the propensity of these reels or spools to break or jam. When this occurs, the entire device must often be completely replaced, frequently at great cost. Additionally, in systems such as those of Fink and Oster, where the barrier material is normally contained in a housing, the physical dimensions of the housing comprise a limitation on the length of the material. Accordingly, the barrier provided is of limited practical usefulness since it is of a limited length. Moreover, in the Fink and Oster systems, the barrier material is permanently mounted to a reel or spool. When this material becomes frayed or otherwise in need of replacement, the entire housing must be replaced.
What is needed, therefore, is an adjustable crowd control system which does not use mechanized means for adjusting the length of the barrier, and which is adapted for facile replacement or reconditioning of the barrier material.